1. Field of the Invention
The present invention relates generally to a valve assembly for recirculating exhaust gases in an internal combustion engine and more particularly to such a valve assembly which includes an exhaust gas back-pressure transducer.
2. Description of the Prior Art
Exhaust gas recirculation valves combined in an assembly with exhaust gas back-pressure transducers are known in the prior art. While the performance of these combination valves has been generally satisfactory, certain disadvantages have been encountered in their manufacture and use.
One disadvantage has been the required use of complex, expensive structure to effect fluid communication between the air bleed chamber of the exhaust gas back-pressure transducer and the atmosphere. Combination valves have heretofore uneconomically utilized passages formed through a structural member of the transducer to effect this communication.
Another disadvantage has been noted in the construction of the poppet valve assembly through which the recirculating exhaust gas flows. Extreme care in the manufacture of this assembly has been required to prevent misalignment of the valve with respect to its seat which would result in unacceptably high leakage through the valve.
Still other disadvantages have been noted in the means previously employed to join portions of the valve assembly to each other. Threaded fasteners and weldments, for example, have been employed to join valve and control sections of the valve housing and to join the valve stem of the EGR valve to the pressure transducer.